Various solders and glasses have been used as an adhesive material and a sealing material of electronic components until now. In particular, gold-tin solder and lead glass have been used because there is a case where heat-resistance of parts of a semiconductor package, a crystal unit, a MEMS, etc. is low that is approximately 400° C. Materials used for these are required, according to their use, to have various characteristics, such as chemical durability, mechanical strength, fluidity, etc. In particular, in case of using them as the sealing material, fluidity at a low temperature is mentioned as an important factor.
In case that the above-mentioned fluidity is insufficient, it is not possible to obtain the characteristics required in each electronic component because there is a risk of leaking out from a sealed part. Therefore, gold-tin solder and lead glass showing a sufficient fluidity at 400° C. or lower have been used. In Patent Publication 1, the gold-tin solder is used for manufacturing a piezoelectric vibrator incorporating a crystal unit, and sealing at 250° C. to 500° C. is disclosed. On the other hand, gold-tin solder is high-priced and lead glass contains a large amount of PbO which has a heavy burden on a human body and on the environment. Therefore, an alternative material has been required.
As the above alternative material, for example, Patent Publication 2 proposes a V2O5—TeO2 glass and discloses that sealing is possible at a low temperature. In addition, Patent Publication 3 proposes V2O5—TeO2—WO3—P2O5 and V2O5—TeO2—WO3—ZnO glasses. On the other hand, these glasses show low softening points, however, there is a case of lacking fluidity as an important factor for sealing performance.